Shelling (1960) among others have argued that contributions to public goods may be larger if people spread their contributions and give one small contribution at a time. Examining a threshold public good environment, Marx and Matthews (2000) show that multiple rounds may secure a provision level...

We study two provisional fixed-prize mechanisms for funding public goods: an all-pay auction and a lottery. In our setting, the public good is provided only if the participants' contributions are greater than the fixed-prize value; otherwise contributions are refunded. We prove that in this...